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authorKim Phillips <kim.phillips@freescale.com>2014-06-02 19:42:58 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-08 15:31:26 -0700
commit3d713e0e382e6fcfb4bba1501645b66c129ad60b (patch)
tree9b47c38f09df44537b163ca18eabc8c979aa1f04 /drivers/base
parent1cec24c59b4a133fc9c83912996168f511075485 (diff)
driver core: platform: add device binding path 'driver_override'
Needed by platform device drivers, such as the upcoming vfio-platform driver, in order to bypass the existing OF, ACPI, id_table and name string matches, and successfully be able to be bound to any device, like so: echo vfio-platform > /sys/bus/platform/devices/fff51000.ethernet/driver_override echo fff51000.ethernet > /sys/bus/platform/devices/fff51000.ethernet/driver/unbind echo fff51000.ethernet > /sys/bus/platform/drivers_probe This mimics "PCI: Introduce new device binding path using pci_dev.driver_override", which is an interface enhancement for more deterministic PCI device binding, e.g., when in the presence of hotplug. Reviewed-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Alexander Graf <agraf@suse.de> Reviewed-by: Stuart Yoder <stuart.yoder@freescale.com> Signed-off-by: Kim Phillips <kim.phillips@freescale.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/platform.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c48c4acb9b87..148f66a1d49a 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -23,6 +23,7 @@
#include <linux/pm_runtime.h>
#include <linux/idr.h>
#include <linux/acpi.h>
+#include <linux/limits.h>
#include "base.h"
#include "power/power.h"
@@ -191,6 +192,7 @@ static void platform_device_release(struct device *dev)
kfree(pa->pdev.dev.platform_data);
kfree(pa->pdev.mfd_cell);
kfree(pa->pdev.resource);
+ kfree(pa->pdev.driver_override);
kfree(pa);
}
@@ -698,8 +700,49 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
}
static DEVICE_ATTR_RO(modalias);
+static ssize_t driver_override_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ char *driver_override, *old = pdev->driver_override, *cp;
+
+ if (count > PATH_MAX)
+ return -EINVAL;
+
+ driver_override = kstrndup(buf, count, GFP_KERNEL);
+ if (!driver_override)
+ return -ENOMEM;
+
+ cp = strchr(driver_override, '\n');
+ if (cp)
+ *cp = '\0';
+
+ if (strlen(driver_override)) {
+ pdev->driver_override = driver_override;
+ } else {
+ kfree(driver_override);
+ pdev->driver_override = NULL;
+ }
+
+ kfree(old);
+
+ return count;
+}
+
+static ssize_t driver_override_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+
+ return sprintf(buf, "%s\n", pdev->driver_override);
+}
+static DEVICE_ATTR_RW(driver_override);
+
+
static struct attribute *platform_dev_attrs[] = {
&dev_attr_modalias.attr,
+ &dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(platform_dev);
@@ -755,6 +798,10 @@ static int platform_match(struct device *dev, struct device_driver *drv)
struct platform_device *pdev = to_platform_device(dev);
struct platform_driver *pdrv = to_platform_driver(drv);
+ /* When driver_override is set, only bind to the matching driver */
+ if (pdev->driver_override)
+ return !strcmp(pdev->driver_override, drv->name);
+
/* Attempt an OF style match first */
if (of_driver_match_device(dev, drv))
return 1;